The primary goals of this study are: 1) To document, on the basis of circulating hormone levels and menstrual history, a pre-menopausal woman's menstrual phase at the time of her primary breast cancer surgery (follicular vs. luteal); 2) To study any association between menstrual cycle phase (follicular vs. luteal) at breast cancer surgery and disease-free survival at 5 years; 3) To compare these breast cancer patient's menstrual cycle data, as determined by hormone levels and the study-specific menstrual cycle history with what is recorded in the general written record; and 4) To estimate the disease-free survival distribution of those women who undergo a two-stage procedure at which cancer is found at both stages and the procedure is not confirmed to one menstrual cycle phase.